Polygonum amphibium - Willow Grass

Family:	Polygonaceae
Habit:	Perennial
Height:	0.3
Synonyms:	Persicaria amphibia.
Range:	Most of Europe, including Britain, temperate Asia, N. America and S. Africa.

Polygonum amphibium (Willow Grass) is a Perennial which grows to a height of 0.3m . It has a hardness rating of 5.
Willow Grass will flower in January to March. The flowers from this plant are hermaphrodite (has both male and female organs) and they are pollinated by Insects

Soil Information

Willow Grass will grow in light (sandy),medium (loamy),hard (clay) soil. It is not necessary for the soil to be well drained.
The soil prefers the following PH / acid levels :
- pH of less than 6, Acidic soils
- pH between 6 and 8, Neutral soils
- pH greater than 8, Basic soils
Willow Grass prefers soils

Ideal Planting Locations

Willow Grass can grow in semi or areas with no shade.

Lakes, ponds, slow-flowing rivers and canals, also on banks by the river[17, 187].

Planting places suited to this plant described below.

• Is a pond plant
• A bog garden plant

Cultivation Details

A water or marsh plant growing in water up to 3 metres deep or in boggy soil[187]. This species is hardy to about -25°c[187]. Plants seem to be immune to the predations of rabbits[233]. The leaves are often attacked by the larvae of the water-lily beetle[187]. Plants can either be aquatic with floating ovate-oblong leaf-blades or a leggy marsh plant with lanceolate leaves[187]. Their stems root at the nodes wherever they come into contact with the soil[200].

Edible Uses*

* See disclaimer
Edible Rating: 1/5
Leaves - raw or cooked. The young shoots are eaten in the spring[257]. Seed - cooked[178]. It is rather small and fiddly to utilize.

• Leaves -
• Seed - includes nuts, cereals, peas and beans.

Medicinal Uses*

* See disclaimer
Medicinal Rating: 2/5
The whole plant, but especially the root, is astringent, depurative, skin[145, 172, 178, 207]. An infusion of the leaves and stems has been used to treat stomach pains and children with diarrhoea[257]. The root has been eaten raw, or an infusion of the dried, pounded roots used, in the treatment of chest colds[257]. A poultice of the fresh roots has been applied directly to the mouth to treat blisters[257].

• Astringent - Produces contraction in living tissue, reducing the flow of secretions and discharges of blood, mucus, diarrhoea etc.
• Depurative - Eliminates toxins and purifies the system, especially the blood.
• Pectoral - Relieves respiratory diseases, a remedy for chest diseases.
• Poultice - A moist, usually warm or hot, mass of plant material applied to the skin in the treatment of burns etc.
• Skin - Plants used in miscellaneous treatments for the skin.

Propagation

Seed - sow spring in a cold frame. Germination is usually free and easy. When they are large enough to handle, prick the seedlings out into individual pots and plant them out in the summer if they have reached sufficient size. If not, overwinter them in a cold frame and plant them out the following spring after the last expected frosts. Division in spring or autumn. Very easy, larger divisions can be planted out direct into their permanent positions. We have found that it is better to pot up the smaller divisions and grow them on in light shade in a cold frame until they are well established before planting them out in late spring or early summer.

Known Hazards

Although no specific mention has been made for this species, there have been reports that some members of this genus can cause photosensitivity in susceptible people. Many species also contain oxalic acid (the distinctive lemony flavour of sorrel) - whilst not toxic this substance can bind up other minerals making them unavailable to the body and leading to mineral deficiency. Having said that, a number of common foods such as sorrel and rhubarb contain oxalic acid and the leaves of most members of this genus are nutritious and beneficial to eat in moderate quantities. Cooking the leaves will reduce their content of oxalic acid. People with a tendency to rheumatism, arthritis, gout, kidney stones or hyperacidity should take especial caution if including this plant in their diet since it can aggravate their condition[238].

Other Uses

Tannin is obtained from the plant[145]. No more details, but it is likely to be from the root.

• Tannin - An astringent substance obtaied from plants, it is used medicinally, as a dye and mordant, stabilizer in pesticide etc.

Cultivars

no recorded cultivars

References

Flora of the British Isles.
Clapham, Tootin and Warburg.
Author: Clapham, Tootin and Warburg.
Rating:
Publisher : A very comprehensive flora, the standard reference book but it has no pictures.
Date of Publication : 1962

The New RHS Dictionary of Gardening. 1992.
Huxley. A.
Author: Huxley. A.
Rating:
Publisher : Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
Date of Publication : 1992

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